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2001 Ford Explorer Sport Trac: Diagnosing P0401, P0171, and P0174 Emissions Codes

Model: 2001 Explorer Sport Trac Fault Code: P0171 Posted: 2009-09-25 15:15

During my recent emissions inspection, my 2001 Ford Explorer Sport Trac triggered three diagnostic trouble codes: P0401, P0171, and P0174. I anticipated a failure due to the 'Check Engine' light, but I hoped these codes would point me toward a specific issue. After performing a tune-up and inspecting all intake lines for holes, no visible damage was found. The engine runs smoothly under normal conditions, so I'm trying to resolve this without visiting a repair shop. Any accurate troubleshooting tips or common causes related to these codes would be greatly appreciated.

Related fault codes
P0171P0174P0401
Comments (1)
Anonymous 2009-09-25 17:00

P0401 typically indicates a problem with the Diesel Particulate Filter Emission (DPFE) sensor. Codes P0171 and P0174 may point to issues such as a hole in the PCV hose, leaking intake manifold O-rings, or a dirty or faulty Mass Air Flow (MAF) sensor. These are common causes on 2001 Ford Explorer Sport Trac models and should be checked systematically.